The present invention relates to an apparatus and an immersion lance for injecting a gas-laden refining agent or powdered-particles into molten metal in a ladle or converter.
It is generally preferable to provide as many lances as there are ladles or converters to facilitate up-and-down movement, installation, replacement, and servicing of the lances. Speeding up of reactions such as desulphurization requires that the lances have a plurality of nozzles for injecting a refining agent into the molten metal. Known multinozzle lances are disadvantageous in that the refining agent or powdered-particles tends to get deposited in the area where the nozzles are branched off from a single introduction tube. The deposited material eventually chokes the introduction tube and some of the nozzles, making the refining reaction insufficient and allowing the molten metal to back-flow into the choked nozzles. To eliminate the above shortcomings, it has heretofore been necessary to lower the ratio of solid material to gas in the refining agent, reduce the load of the ladle, and check and clean the nozzles each time the lance is put into operation. Therefore, the prior art multinozzle lance is inefficient for steel production.
Another problem with the conventional multinozzle lance is that only one supply nozzle and feed pipe is connected to the multinozzle lance, an arrangement which fails to control the rates of injection of the refining agent and gas flow rate for each of the nozzles in the lance.